This invention relates generally to an automatically settable date printing device, and more particularly a date printing device adapted for use in mailing machines having a postage meter, and which is automatically settable by the postage meter so as to print an appropriate date whenever the mailing machine is in operation. Although the present invention has utility in any situation in which it is desired to print sequential dates on some form of document, it is intended primarily for use in mailing machines and is disclosed in this environment.
Postage meters of one type or another have long been well known, and regardless of the type, the basic function of any meter is to print a postage indicia on an envelope, typically in the upper right hand corner, or on a piece of tape which is then secured to the envelope or to a package, to evidence that proper postage has been paid by the sender.
Indicias printed by postage meters from different manufacturers or in different countries will vary in the specific design of various parts of the indicia, but basically most if not all postage meter indicias include a postage portion, normally located on the right side of the indicia, and an origin and date portion normally located on the left side, the two portions being separated by some form of graphic design. Both portions are printed by settable print wheels in the postage meter which print an amount of postage in the postage portion of the indicia, and a date in the origin and date portion of the indicia; normally, other information, such as the words "U.S. Postage" and the city and state of origin are printed with fixed dies.
It has long been well known that the print wheels for the amount of postage are automatically set depending on the amount of postage which is required for a particular envelope. In modern postage meters, the wheels are set either by a mechanical mechanism actuated by a plurality of levers which are moved by the operator of the meter in accordance with the amount of postage desired, or by an electronic keypad input which actuates a mechanical print wheel setting mechanism. In either event, the amount of postage for any particular operation of the meter can be quickly and conveniently changed as necessary.
The periodic setting of the date printing wheels remains a problem of major concern to postage meter manufacturers and users because no practical system has been developed for setting the printing wheels automatically from a single source of drive and in a rotary type meter. Although there have been a few attempts at automatic setting for the date printing wheels, they are almost universally set by hand at the appropriate time. Typically, the month wheel is set on the last day of the previous month or the first day of the new month; the day wheels are set at the end of the previous business day or the beginning of the new day; and the year wheels are set at the end of the current year. The wheels are usually set by the operator opening a cover over the printing drum assembly and turning each individual print wheel by turning a plurality of thumb wheels connected to the print wheels with a pick or his finger to move the print wheels to position the proper month, day or year numbers to the printing position.
There are several drawbacks and disadvantages with this type of print wheel setting system, the end result of all of them being that an incorrect date is printed on the envelope. For one thing, the meter operator may forget to change the date wheels each day, resulting in today's mail bearing at least yesterday's if not an earlier date. Or he may inadvertently advance one or more print wheels too far, with the result that today's mail may bear tomorrow's or a still later date. Some operators dislike setting the date wheels because of the possibility of the operator's fingers coming into contact with exposed portions of the print wheels which are coated with ink which is very difficult to remove. Still further, manual setting of print wheels opens the obvious possibility of fraud by intentionally misdating mail. Also, having a correct date is a requirement of the Postal Service since an indicia is not legal proof of posting. It is therefore apparent that a means for automatically setting the date print wheels on postage meters would obviate if not eliminate these problems.
As briefly mentioned above, there have been a few attempts to development a mechanism for automatically setting date printing wheels in non-rotary type meters, but none so far has met with wide commercial success for one reason or another. The most significant obstacle to developing a simple and efficient automatic date print wheel setting device is the fact that the items of information on date print wheel are not presented in consistent units and increments and precedence order, as is the case with conventional serial number counting or printing devices. In such a device, a series of wheels bearing numbers from 0 to 9 are rotatably mounted in coaxial relationship on a shaft. Each wheel has a single transfer tooth mounted adjacent the peripheral surface of the wheel which meshes with a transfer gear mounted on a second shaft disposed in spaced parallel relation with the first shaft. This gear also meshes with a plurality of teeth mounted on the next adjacent wheel so that the first wheel drives the second wheel through the transfer gear. This structure repeats for as many wheels as there are in the counting or printing device. The arrangement of the gearing is such that, from a single input to the lowest order wheel, each time any wheel makes one revolution, the transfer gear associated with that wheel causes the next higher order wheel to move 1/10th of a revolution, or one number. Thus, each increment of movement of all of the wheels results in a sequential change in the readout of the device.
With dating, however, the arrangement is complicated by the fact that the information required on the printing wheels cannot be presented in increments of 10, nor in even increments of any other number. For example, there are nine days with single digit numbers, 10 days with numbers commencing with the numerals 1 and 2, and one or two days commencing with the numeral 3, depending on the month. Also, there are 28, 30 or 31 days in a month, depending on the month, and there are 12 months in the year. (And every four years, there is one month with 29 days.) Thus, to print a date, two wheels are required, a units day wheel bearing numbers from 0 to 9 around its periphery, and a decade day wheel bearing numbers from 0 to 3 around its periphery. And to print the month, one wheel is required bearing 12 items of information around its periphery. If one were to attempt to print consecutive dates with a conventional wheel arrangement as described above, whether graduated in 0-9 or any other consistent number, after the units day wheel would rotate one revolution, it would move the decade wheel from 0 to 1 in the conventional manner. The same operation would occur when the units day wheel reached 0 for the second and third times to move the decade day wheel to 2 and 3 respectively. But, when the units day wheel would reach 1 with the decade day wheel on 3, to indicate the last day of a 31 day month, the next movement of the units wheel would be to 2, which would indicate the 32nd day of the month. Thus, each successive incremental movement of the units day wheel after the 31st day would indicate additional days of the month from the 32nd to the 39th days, which of course do not exist. What should happen is that the next movement of the units wheel would move the units wheel back to 1 and the decade wheel to 0 or to a blank space to indicate the first day of the next month. Obviously this can not occur merely by turning the units wheel one more increment of movement, as would be the case in a conventional serial number counter or printing device. Thus, it is apparent that a conventional serial number printing device simply cannot be modified to print sequential dates.
Previous attempts to develop an automatic date setting device for a postage meter have resulted in rather cumbersome mechanisms which utilized a series of external driving members for independently moving the date print wheels, the driving members being actuated by separate solenoids or stepping motors, the sequence of operation of which are controlled by means of a suitable timing device such as an electronic calendar. At the appropriate time, such as each day at midnight, the microprocessor would trigger the solenoid or stepping motor to actuate the appropriate driving member to rotate the corresponding print wheel the proper increment of movement. For example, each day of the month, the units wheel, which is numbered from 0 to 9, would be moved 1/10th of a revolution; on the 10th, 20th, and 30th days the decade wheel, numbered from 0 to 3, would be moved 1/3 of a revolution; and on the 28th, 30th or 31st day, depending on the particular month, the month wheel, which bears the identification of the twelve months, would be moved 1/12 of a revolution.
A major drawback of this type of system is the relatively high cost which results from the duplication of structure required to drive each print wheel independently of the others. In addition, the electronic processor for controlling each of the operational inputs must be capable of keeping track of where each print wheel is at all times in order to know how to sequence the next operation of each wheel, thereby resulting in a considerably more complex processor than would be required of one which merely had to cycle once per day, as would be the case for a conventional serial number printer. This system would be inherently more unreliable and occupy more space.